docs: def _check(self):
          """Check final CRC."""
          final = self._md_context.digest()
          exp = self._inf._md_expect
          if exp is None:
              return
          if final is None:
              return
          if self._returncode:
              check_returncode(self, '')
          if self._remain != 0:
              raise BadRarFile("Failed the read enough data")
          if final != exp:
              raise BadRarFile("Corrupt file - CRC check failed: %s - exp=%r got=%r" % (
                  self._inf.filename, exp, final))